# wget https://download.oracle.com/otn_software/linux/instantclient/211000/oracle-instantclient-devel-21.1.0.0.0-1.x86_64.rpm
# wget https://download.oracle.com/otn_software/linux/instantclient/211000/oracle-instantclient-sqlplus-21.1.0.0.0-1.x86_64.rpm
# wget https://download.oracle.com/otn_software/linux/instantclient/211000/oracle-instantclient-basic-21.1.0.0.0-1.x86_64.rpm

# rpm -ivh oracle-instantclient-devel-21.1.0.0.0-1.x86_64.rpm
# rpm -ivh oracle-instantclient-sqlplus-21.1.0.0.0-1.x86_64.rpm
# rpm -ivh oracle-instantclient-basic-21.1.0.0.0-1.x86_64.rpm
# yum -y install tree
# tree /usr/lib/oracle/
# code /usr/lib/oracle/21/client64/lib/network/admin/tnsnames.ora

# code /etc/profile
# ```
# #oracle19.5
# export ORACLE_BASE=/usr/lib/oracle/21
# export ORACLE_VERSION=21
# export ORACLE_HOME=/usr/lib/oracle/$ORACLE_VERSION/client64
# export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH
# export SQLPATH=$ORACLE_HOME/lib/network/admin
# export TNS_ADMIN=$ORACLE_HOME/lib/network/admin
# export NLS_LANG=AMERICAN_AMERICA.AL32UTF8
# export NLS_LANG="Simplified Chinese_china".ZHS16GBK
# export PATH=$PATH:$HOME/bin:$ORACLE_HOME/bin
# ```